Effect of UV radiation on the optical properties of PANI-Cu/PC and PANI-Cu/PC-PBT nanocomposites

Abstract

Polyaniline-copper/Polycarbonate (PANI-Cu/PC) and polyaniline-copper/Polycarbonate-polyester (PANI-Cu/PC-PBT) nanocomposites (NCPs) were fabricated using chemical oxidative and casting techniques. The morphology of the prepared NCPs was studied using scanning electron microscopy. The optical absorption spectra of these NCP samples have been recorded in the wavelength range 250–850 nm at room temperature. Optical parameters such as Urbach energy (Eu ), optical bandgap (Eg ), refractive index (n), real (ϵ ′) and imaginary (ϵ ″) parts of complex permittivity have been evaluated. The induced modifications in the optical properties of the UV irradiated NCPs have been studied as a function of UV fluence. The values of optical bandgap of the blank PANI-Cu/PC and PANI-Cu/PC-PBT NCP samples were found to be 3.92 and 3.86 eV, respectively. These values decreased to 3.57 and 3.08 eV upon raising the UV fluence up to 120 J/cm2 due the dominance of crosslinking that destroys crystallinity and increases the amorphous phase. This was associated with an increase in Urbach energy, refractive index and dielectric constant. The obvious reduction in the optical bandgap of the UV irradiated PANI-Cu/PC-PBT NCPs makes it of great interest in optoelectronic devices applications.